Kristin Cavallari pushes her son Camden in a stroller in Los Angeles, California on September 28, 2012.Credit: WENN.com

Kristin Cavallari has already had to make a tough parenting decision -- and her son is barely 6 months old! The 26-year-old first-time mom says she has chosen to stop breastfeeding baby Camden.

"It's hard," the former Hills reality star told Hollywood Life on Jan. 29. "It was the hardest part of the whole thing and no one tells you that. I was a slave to pumping." As an alternative to breast milk, Cavallari is feeding baby Camden "a goat milk concoction that [fiance] Jay [Cutler] found."

When Us Weekly chatted with the new mom in August 2012, she attributed her slim post-baby body, as many moms have, to breastfeeding. "I started working out when he was 4 weeks old," she said. "Breastfeeding honestly burns 500 calories a day, so that's been very helpful. And I'm a healthy eater in general, so I've just maintained a healthy lifestyle."

While Cavallari may have control over what type of milk her son drinks, the new mom admits she won't be able to stop Camden from playing football like his Chicago Bears quarterback dad, Cutler, 29 -- but she's going to try!

"I will try to steer Cam in a different direction, maybe a sport that isn't so aggressive," she told DNAinfo.com. "Maybe baseball -- something where he doesn't have to get hit."

But Cutler's fiance added, "At the end of the day, I think if he wants to play football, I don't know if I'm gonna have too much control over it. How can your dad be a football player and you tell them that they can't do it?"